Industrialized countries rely upon efficient distribution systems for both raw materials and finished goods. Large objects and bulk commodities are typically transported by standard sized shipping containers, railway cars, tractor/trailers, and the like. It is important to the safety of the cargo as well as the transport container that the stowed cargo be stabilized for shipment. Where cargo is allowed to shift during transport, the cargo can naturally become damaged due to collisions between the cargo itself or between the cargo and the sidewalls of the shipping container. Perhaps more importantly, however, the shifting of the cargo, especially side shifting cargo, can unbalance the container or change the center of mass of the container. Where the shipping container is a vehicle, such as a railway car or tractor/trailer, shifting of the cargo can create a dangerous situation and sometimes cause the vehicle to tip over.
Accordingly, it has long been the custom to stow cargo in a container as carefully as possible and in a manner that substantially eliminates void spaces thereby minimizing the possibility of cargo shifts. In many circumstances, however, the nature of the cargo does not lend itself to such careful packing or it is inefficient from a labor or weight standpoint to completely pack a container with cargo. This is especially true where the cargo comprises large objects or palletized commodities. Therefore, in order to fill the open regions between cargo, it is desirable to provide some sort of dunnage or load spacing device between the cargo and the sidewalls of the container. These dunnage devices or void fillers should be constructed to withstand loading shifting forces typically encountered during cargo transport but also be relatively light weight so as to not unduly increase the shipping load. Furthermore, it is preferable that the void fillers be expandable for use yet be collapsible into a smaller dimension either for shipment to the user or for storage.
One example of such a void filler is described in U.S. Pat. No. 4,494,897 issued 22 Jan. 1985 to Rogers discloses a void filler manufactured of corrugated cardboard as a "tube within a tube" construction. Here, an outer housing is formed as a four-sided tubular member that has open ends and a longitudinal axis extending therethrough. The sides of the outer housing are centrally creased to allow the sides to outwardly bow so that the housing may collapse into a flat configuration. An inner tubular core is disposed within the outer housing in the form of a single cell honeycomb structure that has an axis oriented perpendicularly to the axis of the outer housing. This inner core may likewise expand and collapse, and it is secured to the top and bottom of the housing so that the outer housing and the inner core expand and collapse as a unit. The inner core thus resists compressive forces between the sides of the outer housing when in the expanded configuration.
A somewhat similar structure is shown in U.S. Pat. No. 4,865,889 issued 12 Sep. 1989 to Boyse. In this patent, a plurality of honeycomb cells are organized in a plurality of columns between a pair of outer sheets. Side or deck sheets flank opposite open ends of the honeycomb array and are secured to the outer sheets by flange portions. The deck sheets include fold lines to allow the deck sheets to collapse along with the honeycomb array.
Other prior patents describe void fillers, or pallets which ma be employed as void fillers, having a honeycomb construction. For example, U.S. Pat. No. 3,405,659 issued 15 Oct. 1968 to Hees shows a honeycomb array that is mounted between stiffer tab sheets. The Hees structure is similar to that described in the Boyse patent except that the honeycomb array is formed by joined rows and columns of honeycomb cells and the deck sheets are eliminated. U.S. Pat. No. 4,386,881 issued 7 Jun. 1983 to Liebel is similar to Hees but provides an improved suspension structure for the honeycomb array. U.S. Pat. Nos. 3,079,876 and 3,079,877, each issued 5 Mar. 1963 to Doane show pallet constructions using a honeycomb inner core structure between folding deck panels, and these pallet constructions can be used, if desired, as void fillers.
Although the above void fillers are believed suitable for use in spacing cargo for shipment, they are generally more complex manufacture or construction. Accordingly, there remains a need for improved void fillers that are simpler to produce yet which retain all of the advantages of a light weight device of sufficient strength to be used to space cargo during transport. Therefore, there is a need for improved methods of manufacture of void fillers in order to reduce the costs thereof.